CHAPTER II. 

 OPINION AND PROBABILITY. 



262. NATURE OF PROBABILITY : CUMULATIVE EVIDENCE : 

 &quot; PRACTICAL &quot; CERTITUDE. When the evidence, whether mediate 

 or immediate, on which our assent to a judgment is based, ex 

 cludes all prudent fear of error, our assent is firm ; and this firmness 

 of assent is termed certitude (248). When a normally constituted 

 mind would not deem the evidence sufficient to exclude all such 

 fear from its assent, the latter is called opinion. The intellectual 

 motives, or reasons, which produce such assent, are described as 

 &quot; probable evidence &quot;. In the presence of such evidence we can 

 not be sure that our judgment is true, that it represents, even 

 partially, the reality as it is ; but we can recognize in the judg 

 ment a certain degree of verisimilitude : that it is more or less 

 like the truth, or likely to be true ; or, again, a certain degree of 

 probability : that the judgment is more or less probable, i.e. capable 

 of being proved, established, demonstrated, later on ; and we will 

 therefore give or at least ought to give to such a judgment a 

 degree of assent proportionate to the weight of the evidence. 

 While, therefore, opinion is the subjective mental assent, we may 

 define the probability or verisimilitude of a judgment as the degree 

 of likelihood, estimated from the evidence in favour of the truth of the 

 judgment, that the latter is really true. 



Probability, therefore, is not the &quot; approach &quot; or &quot; approxima 

 tion &quot; of a judgment to truth, to conformity of the mind with 

 reality, in the sense that the Judgment itself is more or less true, but 

 only in the sense that the evidence pointing to its truth is more or 

 less strong. 1 The judgment itself, as a mental unit, a mental pro 

 duct, giving one representation of the reality, must be either true or 

 false all the time : it cannot be more or less ; either the mind in 

 assenting to the judgment is in conformity with reality or it is not. 

 There are not, properly speaking, any grades or degrees of con- 



1 Cf. ZIGLIARA, Logica, (42) ; supra, 248. 

 260 



